/*******************************************************************************
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/
package org.apache.nutch.host;

import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.gora.query.Query;
import org.apache.gora.query.Result;
import org.apache.gora.store.DataStore;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.util.StringUtils;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import org.apache.nutch.storage.Host;
import org.apache.nutch.storage.StorageUtils;
import org.apache.nutch.util.NutchConfiguration;
import org.apache.nutch.util.TableUtil;

/**
 * Display entries from the hostDB. Allows to verify that the storage is OK.
 **/

public class HostDbReader extends Configured implements Tool {
	public static final Log LOG = LogFactory.getLog(HostDbReader.class);

	private void read(String key)
			throws ClassNotFoundException, IOException, Exception {

		DataStore<String, Host> datastore = StorageUtils
				.createWebStore(getConf(), String.class, Host.class);

		Query<String, Host> query = datastore.newQuery();
		// possibly add a contraint to the query
		if (key != null) {
			query.setKey(TableUtil.reverseUrl(key));
		}
		// query.setFields(Host._ALL_FIELDS);
		Result<String, Host> result = datastore.execute(query);

		while (result.next()) {
			try {
				String hostName = TableUtil.unreverseUrl(result.getKey());
				Host host = result.get();
				System.out.println(hostName);
				System.out.println(host);
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		result.close();
		datastore.close();
	}

	public static void main(String[] args) throws Exception {
		int res = ToolRunner.run(NutchConfiguration.create(),
				new HostDbReader(), args);
		System.exit(res);
	}

	public int run(String[] args) throws Exception {
		if (args.length > 1) {
			System.err.println("Usage: HostDBReader [key]");
			return -1;
		}
		try {
			String key = null;
			if (args.length == 1)
				key = args[0];
			read(key);
			return 0;
		} catch (Exception e) {
			LOG.fatal("HostDBReader: " + StringUtils.stringifyException(e));
			return -1;
		}
	}

}
